In fuel economy and powertrain efficiency studies, you can use
the Disc Clutch block to model the mechanical power
transfer between common driveline elements such as transmissions,
engines, and differentials.

To approximate the torque response, the Disc Clutch block
implements friction and dynamic models that depend on the clutch lockup
condition. The block determines the locked or unlocked condition based
on an idealized dry clutch friction model. This table summarizes the
logic the block uses to determine the clutch condition.

Clutch Condition

When

Unlocked

ωi≠ωoorTfmax<|JoTi−(Jobi−Jibo)ωi/oJo+Ji|

Locked

ωi=ωoandTfmax<|Ti−Ji(bi+bo)ωiJo+Ji+boωi|

This table summarizes the friction and dynamic models that the
block uses for locked or unlocked clutch conditions.